Comparator Pregain Stages With Switch-Network Offset Cancellation
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Solution Overview
Problem
Conventional comparators face performance issues due to offset errors, which affect their precision in high-precision applications, and existing offset correction methods are sensitive to semiconductor fabrication processes, limiting their compatibility and accuracy.
Innovation Solution
The proposed solution involves a comparator design with multiple pregain stages and a switch network responsive to clock signals, which selectively couples stages and provides feedback paths to cancel offset errors, minimizing sensitivity to fabrication processes and enhancing precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional offset correction methods are used in comparators, then offset errors can be corrected, but the correction is sensitive to semiconductor fabrication processes, limiting compatibility and accuracy
Solution Approach 1:
The comparator is divided into multiple pregain stages (first, second, third pregain stages) with a switch network inserted between them. This segmentation allows the offset cancellation function to be separated from the main comparison function, enabling independent optimization of offset correction while maintaining robustness against fabrication variations.
Solution Approach 2:
A switch network is introduced as an intermediary element between the pregain stages. This switch network, controlled by clock signals, acts as a mediator that selectively couples or decouples stages and provides feedback paths, enabling offset cancellation without requiring precise matching of fabrication parameters.
2Measurement precision
If multiple pregain stages are added to the comparator, then gain and precision are improved, but device complexity increases
Solution Approach 1:
The switch network merges multiple functions into a single integrated structure: it couples pregain stages, provides feedback paths for offset cancellation, and is controlled by clock signals. This consolidation achieves offset correction and signal amplification without proportionally increasing complexity, as the same switch network performs multiple operations.
Solution Approach 2:
The switch network operates periodically based on clock signals, alternating between different coupling configurations. During certain clock phases, it provides feedback paths for offset cancellation; during other phases, it enables normal signal amplification. This periodic operation allows complex functionality to be achieved through time-multiplexed simple operations.
Data Source
AI summary
An apparatus includes a comparator. The comparator includes a plurality of pregain stages, and a switch network coupled to the plurality of pregain stages. The comparator further includes a latch coupled to the plurality of pregain stages.